| High temperature caused by fire may damage the building severely,even make it collapse.In order to make sure that the building has enough fire resistance capacity,the fire resistance of the building structures must be analyzed.In recent years,profiled steel sheeting-concrete composite deck slab has been developed and widely applied in engineering field,Steel composite slab,as a very reasonable structure where steel and concrete aterial strength are completely utilized,has quick construction,good ductility and higher anti-earthquake capacity.At the present time,special method is still ambiguous in criterion,and it also can't meet the need of engineering development.Therefore,a thorough study of fire resistance and fire resistance design method of composite slab has great theoretical value and practical significance.Firstly,in this paper analyzes the thermal and mechanical properties of normal concrete and structural steel at elevated temperatures for composite slab are presented.The thermal properties and the stress-strain relations of steel and concrete in composite slab under high temperature are determined.Secondly, analysis of temperature distribution of composite slabs in fire under fire protection of fire insulation.The ANSYS software is used to analyzed the temperature distribution in composite slab under IS0834 fire.Then , based on the thermal transmission,the fire-resistance behaviors of steel deck-concrete composites continuous slab is simulated under four fire situations, when it is protected by fire insulation.Draw the time-temperature curve for the key point, and then testifies the validity and reliability of model through comparing with the value of the steel composite slab in the fire directly. Verify the effect of fire insulation.At last, the fire-resistance performance of steel sheeting-concrete composite deck slabs is studied, based on the thermal transmission,and the result of temperature field was introduced into the structure program by using the coupling program of ANSYS,the effect on the fire resistance of composite slabs has been discussed in different fire situations. Analyze the advantages of the composite slabs as continuous plates fire resistance ,and propose the fire-resistence measures for the composite slabs in fire. |
